/*
 * Copyright (c) 2007, 2015, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Copyright 2001-2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id: StepIterator.java,v 1.2.4.1 2005/09/06 10:26:47 pvedula Exp $
 */

package com.sun.org.apache.xalan.internal.xsltc.dom;

import com.sun.org.apache.xalan.internal.xsltc.runtime.BasisLibrary;
import com.sun.org.apache.xml.internal.dtm.DTMAxisIterator;
import com.sun.org.apache.xml.internal.dtm.ref.DTMAxisIteratorBase;

/**
 * A step iterator is used to evaluate expressions like "BOOK/TITLE".
 * A better name for this iterator would have been ParentIterator since
 * both "BOOK" and "TITLE" are steps in XPath lingo. Step iterators are
 * constructed from two other iterators which we are going to refer to
 * as "outer" and "inner". Every node from the outer iterator (the one
 * for BOOK in our example) is used to initialize the inner iterator.
 * After this initialization, every node from the inner iterator is
 * returned (in essence, implementing a "nested loop").
 *
 * @author Jacek Ambroziak
 * @author Santiago Pericas-Geertsen
 * @author Erwin Bolwidt <ejb@klomp.org>
 * @author Morten Jorgensen
 */
public class StepIterator extends DTMAxisIteratorBase {

  /**
   * A reference to the "outer" iterator.
   */
  protected DTMAxisIterator _source;

  /**
   * A reference to the "inner" iterator.
   */
  protected DTMAxisIterator _iterator;

  /**
   * Temp variable to store a marked position.
   */
  private int _pos = -1;

  public StepIterator(DTMAxisIterator source, DTMAxisIterator iterator) {
    _source = source;
    _iterator = iterator;
// System.out.println("SI source = " + source + " this = " + this);
// System.out.println("SI iterator = " + iterator + " this = " + this);
  }


  public void setRestartable(boolean isRestartable) {
    _isRestartable = isRestartable;
    _source.setRestartable(isRestartable);
    _iterator.setRestartable(true);         // must be restartable
  }

  public DTMAxisIterator cloneIterator() {
    _isRestartable = false;
    try {
      final StepIterator clone = (StepIterator) super.clone();
      clone._source = _source.cloneIterator();
      clone._iterator = _iterator.cloneIterator();
      clone._iterator.setRestartable(true);       // must be restartable
      clone._isRestartable = false;
      return clone.reset();
    } catch (CloneNotSupportedException e) {
      BasisLibrary.runTimeError(BasisLibrary.ITERATOR_CLONE_ERR,
          e.toString());
      return null;
    }
  }

  public DTMAxisIterator setStartNode(int node) {
    if (_isRestartable) {
      // Set start node for left-hand iterator...
      _source.setStartNode(_startNode = node);

      // ... and get start node for right-hand iterator from left-hand,
      // with special case for //* path - see ParentLocationPath
      _iterator.setStartNode(_includeSelf ? _startNode : _source.next());
      return resetPosition();
    }
    return this;
  }

  public DTMAxisIterator reset() {
    _source.reset();
    // Special case for //* path - see ParentLocationPath
    _iterator.setStartNode(_includeSelf ? _startNode : _source.next());
    return resetPosition();
  }

  public int next() {
    for (int node; ; ) {
      // Try to get another node from the right-hand iterator
      if ((node = _iterator.next()) != END) {
        return returnNode(node);
      }
      // If not, get the next starting point from left-hand iterator...
      else if ((node = _source.next()) == END) {
        return END;
      }
      // ...and pass it on to the right-hand iterator
      else {
        _iterator.setStartNode(node);
      }
    }
  }

  public void setMark() {
    _source.setMark();
    _iterator.setMark();
    //_pos = _position;
  }

  public void gotoMark() {
    _source.gotoMark();
    _iterator.gotoMark();
    //_position = _pos;
  }
}
